1. Field of the Invention
This invention relates generally to absorbent products designed to absorb body fluids and, more particularly, to catamenial receptors designed to be worn within the vagina while receiving catamenia of women and, more particularly, to improvements in tampons having an absorbent body comprising particles of absorbent foam retained as an aggregate within a suitable overwrap or sack.
2. Description of the Prior Art
Tampons of various types and descriptions are well known articles of manufacture. A major departure from prior art tampons is described and claimed in U.S. Pat. No. 3,815,601 issued June 11, 1974 to Jean E. Schaefer, said patent being assigned to the assignee of the instant invention. The Schaefer tampon comprises an absorbent body formed by an aggregate comprising separate, relatively small pieces of resilient, absorbent foam. The foam aggregate is retained within an encasing overwrap or sack having a mesh fine enough to totally contain the absorbent pieces and to prevent their penetration of the overwrap. In a preferred form of the invention, the overwrap is a relatively loose sack formed about the aggregate thereby permitting some relative movement between adjacent pieces of foam and also providing the tampon with a certain degree of flexibility. This flexibility results in a tampon which will conform to its surroundings thereby resulting in increased efficiency and wearing comfort. The tampons are usually stored in the compressed state, usually in a tubular tampon applicator.
The copending, commonly assigned application of Hutchins and Dobson, Ser. No. 506,828 filed Sept. 17, 1974, describes an improvement in the method of making the tampons described in the Schaefer patent. Generally, the method of manufacture is to produce a polyurethane foam, comminute the foam so as to provide particles of suitable size, wash and dry the comminuted foam, then volumetrically measure the amount of uncompressed foam required for each tampon and pack this volume of foam into an overwrap or sack so as to produce a tampon. The application of Hutchins and Dobson is primarily concerned with the improvement in the manufacturing process which comprises applying a small quantity of hydrophobic liquid, such as mineral oil, to the washed and dried foam thereby reducing the tendency of the particles of foam to clump with a resultant improvement in the uniformity of the quantity of foam in each tampon when made with high speed equipment and methods. While the method of Hutchins and Dobson does facilitate the manufacture of the tampons described by Schaefer, and while the resultant tampons are, in general, superior to prior art tampons, tampons made with a lightly lubricated foam exhibit reduced humid expansion, when compared to unlubricated foams, after prolonged storage in the compressed state.
Humid expansion is an important attribute of tampons. Most tampons expand rapidly when contacted with fluid, but this expansion may be too slow to prevent by-passing of the tampon by menses with associated soiling of clothing and embarrassment to the wearer. Tampons which exhibit rapid humid expansion, on the other hand, expand rapidly to conform to the interior surfaces of the vagina, even without liquid contact, thereby essentially eliminating any possibility of by-passing. The reduction in humid expansion rate after prolonged storage in the compressed state exhibited by lightly lubricated foam tampons represents an undesirable characteristic of prior art tampons.